1. Field of the Invention
The present invention relates to a technology for processing a document with an appended radio frequency identification tag.
2. Description of the Related Art
In recent years, there is a tremendous improvement in the quality of images formed using image processing apparatus such as full-color copying machines. As a result, there is an increasing likelihood of forgery of documents such as cash notes and security bills (hereinafter, “specific originals”).
Japanese Patent Application Laid-Open No. H6-105136 proposes an image processing apparatus that includes a correcting unit that corrects characteristics of an inputted color image signal to obtain a corrected image signal; an extracting unit that extracts characteristics in the corrected image signal obtained by the correcting unit; a forgery judging unit that judges similarity between the characteristics extracted by the extracting unit and characteristics of specific originals prepared in advance; and a changing unit that changes contents of processing for the inputted color image signal according to the similarity judged by the forgery judging unit.
Moreover, Japanese Patent Application Laid-Open No. H2-210591 and Japanese Patent Application Laid-Open No. H6-54186 propose techniques for image processing apparatuses that register an image pattern of specific originals in advance, compare a pattern of an inputted image and the registered image pattern to judge similarity between the patterns, and determine whether the inputted image is an image of the specific original to thereby prevent the specific original from being forged.
On the other hand, in “Radio tag for attaching Information to Articles and Applications thereof”, Information Processing Society of Japan, IPSJ Magazine, vol. 40, No. 8, pp. 846 to 850 (August 1999), it is mentioned that an ID element (RFID: Radio Frequency Identification) technology for holding individual information electronically and transmitting the information in a non-contact manner has been developed and started to be applied for identification and management of articles. Note that, as a conventional compression system, a system for converting image data into a frequency component with orthogonal conversion like DCT and quantizing a conversion factor for the frequency component is known. In particular, as a system encoding a multi-valued image using the DCT, the JPEG system standardized by ITU-T and ISO is known. A DCT arithmetic expression of JPEG is as follows.
                    Suv        =                                                            C                ⁡                                  (                  u                  )                                            *                              C                ⁡                                  (                  v                  )                                                      4                    ⁢                                    ∑                              x                =                0                            7                        ⁢                                          ∑                                  y                  =                  0                                7                            ⁢                              syx                *                                  COS                  ⁡                                      [                                                                                            (                                                                                    2                              *                              x                                                        +                            1                                                    )                                                *                        u                        *                        π                                            16                                        ]                                                  *                                                                        (        1        )                                                          ⁢                  COS          ⁡                      [                                                            (                                                            2                      *                      y                                        +                    1                                    )                                *                v                *                π                            16                        ]                                                                              syx        =                              1            4                    ⁢                                    ∑                              x                =                0                            7                        ⁢                                          ∑                                  y                  =                  0                                7                            ⁢                                                                    C                    ⁡                                          (                      u                      )                                                        ·                                      C                    ⁡                                          (                      v                      )                                                                      *                Suv                *                                  COS                  ⁡                                      [                                                                                            (                                                                                    2                              *                              x                                                        +                            1                                                    )                                                *                        u                        *                        π                                            16                                        ]                                                  *                                                                        (        2        )                                                          ⁢                  COS          ⁡                      [                                                            (                                                            2                      *                      y                                        +                    1                                    )                                *                v                *                π                            16                        ]                                                                              u        ,                  v          =          0                ,        1        ,                              ~            7                    ⁢                                          ⁢          where                                                                              C          ⁡                      (            W            )                          =                  [                                                                      1                                      2                                                                                                                    when                    ⁢                                                                                  ⁢                    W                                    =                  0                                                                                    1.0                                                                                                        when                      ⁢                                                                                          ⁢                      W                                        =                    1                                    ,                                      ~                    7                                                                                                                      
However, in the case of a full-color copying machine, each image reading apparatus has a different image reading characteristic. Even if the image reading apparatuses have identical configuration or they look identical, amount of lights emitted from lamps of each image reading apparatus is different depending various factors. Even the specific originals may have various concentrations or the specific originals may be soiled or worn-out which makes an image thereon unclear. Therefore, in the conventional systems, there is a problem in that, since a level of an image signal from an image reading apparatus fluctuates, the accuracy of correctly determining whether an original is a specific original fails.
Even if an image pattern of a specific original is registered in a copying machine, when the image pattern of the specific original is inputted with a magnification thereof changed, it is likely that the specific original is forged because it is judged that similarity between the inputted image pattern and the registered image pattern is low. Therefore, the image pattern of the specific original has to be registered in association with all magnifications. In this case, there is a problem in that a memory with a large capacity is required, determination processing is complicated, and the accuracy of correctly whether an original is a specific original falls.
In addition, in recent years, in accordance with an improvement of an image quality of an image formed by the image processing apparatus such as the full-color copying machine, when a book or the like is copied using a copying machine in a public library or a library in a company, there is a problem of infringement of copyright owned by a publishing company through the copying of the book.